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Last November, contracted with to produce sapphire on a large scale, not the naturally occurring gemstone, but a man-made version. A sapphire screen in future iPhones would be revolutionary because sapphire is a very hard substance and thatwill dramatically reduce incidents of broken phone screens.

Sapphire screens have three short comings. Innovation at Apple seems to have overcome all of these short comings.

First, sapphire is heavier than glass and the trend is to make phones lighter. Second, sapphire is more expensive than glass. Third, oil repelling coatings that are essential to reducing smudges on a screen do not apply well to sapphire.

Apple has overcome the three foregoing shortcomings of sapphire by using a layer approach. Based on the patents filed by Apple, the sapphire iPhone screen is likely to have a base glass layer, main sapphire layer and an ultrathin glass layer on top of sapphire.

On March 27, 2014, the United States Patent and Trademark Office (USPTO) published an Apple patent application titled OLEOPHOBIC COATING ON SAPPHIRE. The application describes a glass layer on top of sapphire layer. Apple has been using oil repellent coating on glass starting with iPhone 3GS. Apple will be able to use its time tested technique for oil repellent on the top thin glass layer.

Apple solves the cost and weight problem by adding a glass layer under the sapphire layer. Apple has applied for a patent to use a laminate structure of sapphire layers to form a screen. From the abstract of the patent application: ‘Various sapphire and laminate structures are discussed herein. One embodiment may take the form of a sapphire structure having a first sapphire sheet with a first sapphire plane type forming the major surface and a second sapphire sheet having a second different sapphire plane type forming the major surface. The first and second sapphire sheets are fused together to form the sapphire structure.’ An interesting embodiment is fusing an outer sapphire layer with an inner glass layer.

This approach still leaves the problem of scratches. Sapphire is a very hard substance and is difficult to scratch. However, by fusing a surface layer of glass on top of sapphire, scratches will still happen but will be less noticeable.